Method and system for estimating input power in a cable modem network
US6782335B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | Sep 26, 2000 |
| Grant date | Aug 24, 2004 |
| Priority date | — |
| Expiry date | Sep 26, 2020 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04L27/00
- WIPO fieldDigital communication
- WIPO sectorElectrical engineering
Abstract
A method for estimating the input power to a cable modem includes generating a look-up table containing AGC integrator accumulator values corresponding to selected frequencies and amplitudes. The look-up table is generated by first constructing a calibration matrix by inputting a plurality of calibration signals having known input frequencies and known input power levels into the cable modem's receiver, and recording AGC integrator accumulator values corresponding to several frequencies and power levels over a selected operating range as calibration points. Next, an interpolation and extrapolation process generates the look-up values corresponding to the frequencies and amplitudes in between the calibration points. During modem operation, the modem estimates the input power by checking the AGC integrator accumulator value corresponding to the input frequency and amplitude. Because the look-up table values are based on the cable modem's actual operating characteristics, the estimated input power will reflect any variations or irregularities in the modem's operation, such as gain non-linearities, frequency ripple, or temperature effects.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.